Contact



Patented D... 20,1938

UNITED STATES CONTACT Chester Peterson, Maplewood, N. J., assignor to The H. A. Wilson Company, a corporation of New Jersey No Drawing. Application April 24, 1937, Serial No. 138,754

6 Claims. (01. zoo-1st) l5 tics may be so much more important than others as to determine the selection of the particular materials. Thus, in circuit breaker mechanisms operating on direct current, the current and voltage conditions in the circuit being made and broken are frequently such that various contact materials suitable. for other uses can not be employed because they have a tendency to build up and stick together. These changes in the contacts interfere with the proper operation of the g5 mechanism and may require frequent repair or replacement of the contact members.

The tendency of contacts to build up and stick together in direct current apparatus is especially pronounced when both points are made of the same material as it is found that with similar contacts made of materials heretofore ordinarily used, such for example as fine silver, a high sharp local peak is produced on one point and a corresponding deep cavity or crater on the other.

When such a peak and crater are formed in an apparatus in which the points move together and apart with a shearing or rubbing action, as is frequently the case, the peak enters the crater and the points interlock and stick even though there is no actioncomparable with welding.

The present invention is accordingly directed to the provision of a novel contact which may be used to great advantage in those forms of circuit breaker mechanism in which the tendency of the contacts to build up and stick together must be minimized, an example of such a contact being an automotive voltage regulator.

The contact of the invention is formed of a silver alloy which includes a substantial amount of manganese, and preferably the silver is in a preponderating amount ranging from about to about 98% of the alloy, and the manganese ranges from about 2% to about 20%. The preferred composition is about silver and about 10% manganese.

Contacts of fine silver have been used for many years in circuit breaker. apparatus and have 5 many desirable physical and electrical characteristics. They are open to the objection, however, that they tend to build up and stick together and thus, a pair of such contacts cannot be used satisfaotorily in a circuit breaker mechanism oper- 10 ating on direct current. I have found that when silver is alloyed with an amount of manganese within the ranges above specified, the resulting alloy produces a contact of the desired properties, and in those forms of apparatus in which dis- 15 similar contacts are to be employed, a silvermanganese contact may be used with one of fine silver or of silver alloyed with one of the metals of the platinum group such as platinum or palladium. In other forms of apparatus, both con- 20 tacts may be made of the new material.

I claim: l

1. A contact for electrical circuit breaker mechanisms composed of a. silver manganese alloy. 25

2. A contact for electrical circuit breaker mechanisms composed of an alloy containing a preponderating quantity of silver and a less amount of manganese.

3. A contact for electrical circuit breaker 3o mechanisms composed of an alloy of silver rang- .ing from 80% to 98%,.and the remainder manganese.

, 4. A contact for electrical circuit breaker mechanisms composed of an alloy containing 5 about 90% silver, and the remainder manganese. 5. In an electrical circuit breaker mechanism, cooperating contacts between which the circuit is to be made and broken, said contacts being of different materials and one contact being com- 49 posed of a metal alloy containing a preponderating amount of silver and a less amount of manganese. l

6. In an electrical circuit breaker mechanism for operation on direct current, cooperating con- 45 tacts between which the circuit is made and broken, said contacts being of difierent materials and the positive contact being composed of an alloy containing a preponderating amount or silver and. a less amount 01 manganese. 5

orms'r'na rn'mason. 

